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Targeted mop-up campaigns

Mop-up campaigns are door-to-door immunizations that are carried out in specific focal areas where the virus is known or suspected to still be circulating. Priority areas include those where polio cases have been found over the previous three years and where access to health care is difficult. Other criteria include high population density, high population mobility, poor sanitation, and low routine immunization coverage.

Examples of successful mop-up campaigns

The Americas

In Peru, after the last reported case of polio in 1991, almost two million children were immunized in a one week door-to-door campaign. Mopping-up in Colombia was essential to finally interrupt transmission. Sustained surveillance for three years following the discovery of the last polio case proved that no more wild poliovirus was circulating in the region. The Americas were certified polio-free in 1994.

The Western Pacific

In the Mekong Delta area of Cambodia, southern Viet Nam and the Lao People’s Democratic Republic, a large mopping-up immunization activity targeting more than one million children was successfully conducted from May to July, 1997. The activity targeted the only known remaining area of wild poliovirus circulation in the WHO Western Pacific Region. Wild poliovirus has not been found in the Western Pacific Region since March 1997, and the Region was certified polio-free in October 2000.